Method for creating narrow trenches in dielectric materials

Abstract

A method for producing narrow trenches in semiconductor devices. The narrow trenches are formed by chemically changing the properties of a first dielectric layer locally, such that the side walls of a patterned hole in the first dielectric layer is converted locally and becomes etchable by a first etching substance. Subsequently a second dielectric material is deposited in the patterned structure and the damaged part of the first dielectric material is removed such that small trenches are obtained.

1. A method for making trenches having a width smaller than 40 nm, the method comprising:
 depositing an etchstop layer onto a substrate; 
 depositing a first dielectric layer on top of the etchstop layer; 
 patterning a temporary structure in the first dielectric layer; 
 modifying the sidewalls of the temporary patterned structure such that a portion of the sidewalls becomes etchable by an etchant; 
 depositing a second dielectric layer within the temporary structure; 
 removing overburden of the second dielectric material such that the upper level of the 
 second dielectric layer equals the level of the first dielectric layer; and 
 selectively removing the portion of the sidewalls with an etchant such that narrow trenches are created, wherein the first and second dielectric materials are resistant to the etchant. 
 
     
     
       2. The method as in  claim 1 , wherein modifying the sidewalls comprises performing at least one of damaging the sidewalls and converting the sidewalls. 
     
     
       3. The method as in  claim 1 , wherein patterning the temporary structure comprises:
 depositing photosensitive layers onto the first dielectric layer; 
 lithographically transferring the temporary structure into the photosensitive layers; and 
 transferring the temporary structure into the first dielectric layer by dry-etching. 
 
     
     
       4. The method as in  claim 1 , wherein at least one of a hardmask and a metal hardmask is deposited on top of the first dielectric material. 
     
     
       5. The method as in  claim 1 , wherein patterning the temporary structure and modifying the sidewalls of the temporary structure are performed simultaneously. 
     
     
       6. The method as in  claim 5 , wherein patterning the temporary structure and modifying the sidewalls of the temporary structure are performed by an oxidizing plasma. 
     
     
       7. The method as in  claim 6 , wherein the plasma comprises oxygen. 
     
     
       8. The method as in  claim 6 , wherein the plasma comprises at least one (hydro)fluorocarbon compound. 
     
     
       9. The method as in  claim 1 , wherein the etchant comprises a wet etchant that includes HF. 
     
     
       10. The method as in  claim 9 , wherein the etchant comprises less than 5 wt. % HF. 
     
     
       11. The method as in  claim 1 , wherein the first dielectric material comprises a SiCO(H) material. 
     
     
       12. The method as in  claim 1 , wherein the second dielectric material comprises a spin-on low-k material. 
     
     
       13. The method as in  claim 1 , wherein modifying the sidewalls of the temporary structure is performed by an UV/ozone treatment with addition of an oxidizer. 
     
     
       14. The method as in  claim 1 , wherein modifying the sidewalls of the temporary structure is performed by a SCCO 2  treatment with addition of an oxidizer. 
     
     
       15. The method as in  claim 1 , wherein the portion of the sidewalls has in-plane dimensions smaller than 50 nm. 
     
     
       16. The method as in  claim 1 , wherein the narrow trenches have an aspect ratio of about 10 to 1. 
     
     
       17. The method as in  claim 1 , further comprising:
 depositing a barrier layer within the narrow trenches; and 
 depositing a conductive material onto at least one of a seed layer and the barrier layer to create completely filled trenches. 
 
     
     
       18. The method as in  claim 17 , further comprising:
 depositing the seed layer onto the barrier layer. 
 
     
     
       19. The method as in  claim 1 , wherein the narrow trenches have a width that is less than 40 nm.